In November the Missouri Department of Transportation placed several “sound cannons” on Interstate 435 in Kansas City and on Interstate 70 near Columbia to see if they could make drivers slow down in work zones.

The Kansas City Star (http://bit.ly/1puWbkJ ) reports the devices were provided by San Diego-based LRAD Corp., which initially developed the long-range acoustic devices to warn strangers getting too close to U.S. ships following the USS Cole attack in Yemen in 2000.

Critics complain that the technology startles divers inside of their cars, and last month lawmakers in Jefferson City questioned whether MoDOT had spent money on the devices, which it didn’t.